U.S. prosecutors in New York have launched an insider-trading probe into a leak of sensitive information from the Federal Reserve in 2012, the Wall Street Journal reported on Wednesday, citing people familiar with the matter.

The paper said the Commodity Futures Trading Commission was also looking into whether anyone had violated insider-trading rules in 2012 when the firm at the center of the investigation, Medley Global Advisors, disclosed to its clients details about the Fed's plans for further economic stimulus.